Peptide-lipid constructs and their use in diagnostic and therapeutic applications

ABSTRACT

Peptide-lipid constructs of the structure L-S—F are disclosed, where F is a peptide, S is a spacer covalently linking F to L via an oligomer of ethylene glycol, and L is a diacyl- or dialkyl-glycerolipid (including glycerophospholipids). The spacer ideally has 6 to 14 ethylene glycol repeats, corresponding to PEG with a molecular weight of approximately 250 to 600. Also disclosed is a method of detecting reactive antibodies in serum by contacting serum with cells modified to incorporate a peptide-lipid construct, where the peptide is an epitope of the antibody, and determining the degree of aggluthination of the cells.

TECHNICAL FIELD

The invention relates to methods for effecting qualitative andquantitative changes in the levels of peptide expressed at the surfaceof cells and multi-cellular structures, and constructs for use in suchmethods.

In particular, the invention relates to peptide-lipid constructs for usein diagnostic and therapeutic applications, including serodiagnosis.

BACKGROUND ART

The ability to effect qualitative and quantitative changes in the levelof peptides expressed at the surface of cells and multi-cellularstructures provides for a range of diagnostic and therapeuticapplications.

Qualitative and quantitative changes in the level of peptides expressedat the surface may modify trans-membrane transport, cell-solute andcell-cell interactions, and thus the functionality of the modified cellor multi-cellular structure.

Known methods of effecting such changes include gene manipulation,chemical modification of endogenous membrane peptides, and “cell surfacepainting” using lipid anchors such as GPI.

The specification accompanying international application numberPCT/NZ2005/000052 (publication number WO 2005/090368) describes thepreparation of water soluble carbohydrate-lipid constructs for use inmethods of effecting qualitative and quantitative changes in the levelof carbohydrates expressed at the surface of cells and multicellularstructures.

The specification accompanying international application numberPCT/NZ2006/000245 (publication number WO 2007/035116) describes anothermethod for the preparation of water soluble carbohydrate-lipidconstructs where the carbohydrate is the polymer hyaluronic acid. Use ofthe construct to modify embryos and promote association with endometrialcells is described.

Relatively little work has been performed on the site-directed couplingof peptides to phospholipids as individual components prior to theirincorporation in self assembling lipid structures, such as liposomes, oras would be required to provide peptide-lipid constructs for use inmethods of effecting qualitative and quantitative changes in the levelof peptide expressed at the surface of cells and multicellularstructures.

A variety of standard techniques have been described for the covalentcoupling of peptides to liposomes surfaces.

Martin et al (1990) has reviewed methods of attaching moieties includingpeptides, to the surface of liposomes.

Blume et al (1993) describes the coupling of the water solubleGlu-plasminogen to liposomes by the method described by Kung andRedemann (1986). The chemical ECDI(1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride) is used toactivate the liposomes prior to incubation of the activated liposomesuspension with Glu-plasminogen. Proteo-PEG-coated liposomes withGlu-plasminogen covalently attached to the ends of thedistearylyphosphatidylethanolamine (DSPE)-PEG-COOH are provided.

Haselgrübler et al (1995) describes a heterobifunctional crosslinkerused to facilitate the preparation of immunoliposomes. The crossllinkeris synthesised from a diamine derivative of poly(ethylene glycol) (PEG,average molecular weight 800 dalton (18mer)). The crosslinker has2-(pyridylthio)propronyl (PDP) and N-hydroxysuccinimide ester (NHS) asfunctional groups.

Ishida et al (2001) describes the preparation of liposomes bearingpolyethylene glycol-coupled transferrin. Transferrin was conjugated viathe terminal carboxyl residue of DSPE-PEG-COOH. The liposomes wereproposed as having utility in in vivo cytoplasmic targeting ofchemotherapeutic agents or plasmid DNAs to target cells.

Massaguer et al (2001) describes the incorporation of a peptide sequence(GGRGRS) and hydrophobic derivatives to the surface of chemicallyactivated liposomes. The incorporation was carried out through thecarboxyl group of N-glutaryl dipalmitoyl phosphatidyl choline (NGPE).

Massaguer et al (2001) noted that considering potential in vivoapplications, where sterility and simplicity would be some of the mostimportant requirements, processes based on chemical reactions on thesurface of liposomes involving extra steps would be more difficult to bescaled up at the industrial level. A hydrophobic derivative of thepeptide sequence was identified as providing optimal properties forincorporation to the surface of liposomes.

Chung et al (2004) describe the antigenic determinant shielding effectof DOPE-PEG incorporated into the membranes of cells and speculatedconcerning the potential of lipid-PEG(n)(s) to regulate biological cellresponses and the extension of this concept to the introduction offunctional molecules at the end of the PEG chain.

Kato et al (2004) describe a method for anchoring of macromolecularproteins into the membranes of living mammalian cells. Adioleylphosphatidylethanolamine (DOPE) derivative coupled withhydrophilic poly(ethylene glycol) (PEG80) was used as the syntheticmembrane anchor. Peptides were conjugated at the distal terminal of thePEG moiety via an amino-reactive N-hydroxysuccinimide derivative of thesynthetic membrane anchor.

The PEG80 moiety facilitated solublisation of the synthetic membraneanchor in water. As noted by Kato et al (2004) if the anchor isinsoluble in water, undesirable and complicated processes such asliposome preparation and the fusion of liposomes with the cell membranemay be required to anchor the conjugates into the cell membrane.

An additional advantage noted by Kato et al (2004) was that syntheticmembrane anchors with high hydrophile-lipophile balance values(attributable to PEG spacer with a high number of oxyethylene units)were concluded to have no cytolytic activity. However, difficultiesarise in the use of synthetic membrane anchors including a PEG spacerwith a high number of oxyethylene units.

Firstly, the expression of the conjugative peptide or other endogenouscell surface peptides may be masked by the PEG spacer. Secondly, a PEGspacer with a high number of oxyethylene units may elicit non-specificadherence of protein (including antibodies in certain individuals)and/or the non-specific activation of the complement cascade.

Winger et al (1996) describes the conjugation of bromoacetylated DSPEwith a thiol terminated decapeptide comprising at its C-terminus theminimal human thrombin-receptor peptide agonist (HS-SerPheLeuLeuArgAsn).

Hashimoto et al (1986) describes the conjugation of iodoacetylated DSPEwith thiolated compounds.

A need exists for peptide-lipid constructs that can be used to effectqualitative and quantitative changes in the level of peptides expressedat the surface of cells and multi-cellular structures.

It is an object of this invention to provide peptide-lipid constructsthat satisfy this need or at least provide a useful choice.

DISCLOSURE OF INVENTION

In a first aspect the invention provides a method of detecting reactiveantibody in the serum of a subject including the steps of:

-   -   Contacting a sample of the serum with a suspension of cells        modified to incorporate a peptide-lipid construct of the        structure (L-S—)_(i)F(—S-L)_(j) to provide a mixture;    -   Incubating the mixture for a time and at a temperature        sufficient to allow agglutination; and    -   Determining the degree of agglutination of the cells in the        mixture;

where:

-   -   F is a peptide comprising an epitope for the reactive antibody;    -   S is a spacer covalently linking F to L; and    -   L is a lipid selected from the group consisting of diacyl- and        dialkyl-glycerolipids, including glycerophospholipids; and    -   i and j are independently 0 or 1,

Optionally, the method includes the preliminary step of:

-   -   Adding an amount of the peptide to the sample of the serum;

where the amount of the peptide is sufficient to neutralize non-specificagglutination or confirm specificity of the reactive antibody.

Optionally, the method includes the intermediate step of:

-   -   Adding an anti-subject globulin antibody to the mixture prior to        determining the degree of agglutination of the cells of the        mixture.

Preferably, the subject is a human.

Preferably, the cells are red blood cells.

Preferably, the anti-subject globulin antibody is anti-human globulin(AHG) antibody.

Preferably, the reactive antibody is reactive to an antigen selectedfrom the group consisting of: Glycophorin A, Glycophorin B, or mutationsthereof (including the MNS blood group system).

The spacer (S) is selected to provide a water soluble peptide-lipidconstruct.

Preferably, S is a spacer covalently linking F to L via an oligomer ofethylene glycol.

Preferably, the structure of the peptide-lipid construct includes thesubstructure:

where M is a monovalent cation (M⁺), n is 6 to 14 and * is other than H.

More preferably, the structure of the peptide-lipid construct is either:

where M is a monovalent cation (M⁺), n is 6 to 14, w is 1 or 2, the sumof x and y is greater than 5, z is greater than 5, and * is other thanH.

Preferably, the sum of i and j is 1.

Optionally, F is a peptide including a proximal terminal sequence (PTS)selected to promote solubility of the peptide.

In a preferment of this option, the PTS of the peptide is selected fromthe group consisting of:

SerLysLysLysLysGly AlaAlaAlaAla GlySerGlySerGly

Preferably, F is a peptide comprising an epitope of antigens selectedfrom the group consisting of: Glycophorin A, Glycophorin B, or mutationsthereof (including the MNS blood group system).

More preferably, F is a peptide selected from the List of Peptides.

Most preferably, F is a peptide selected from the group consisting of:

GlnThrAsnAspLysHisLysArgAspThrTyrAlaAlaAlaAlaAlaCysGlnThrAsnAspLysHisLysArgAspThrTyrGlySerGlySerGlyCysGlnThrAsnAspMetHisLysArgAspThrTyrGlySerGlySerGlyCys         SerSerGlnThrAsnAspLysHisLysArgAspThrTyrCys                  ThrTyrProAlaHisThrAlaAsnGluValCys                        ProAlaHisThrAlaAsnGluValCys                  SerGlnThrAsnAspLysHisLysArgAspCysAlaAlaAlaAlaValMetTyrAlaSerSerGly GlySerGlySerGlyValMetTyrAlaSerSerGly

Preferably, L is a glycerophospholipid. More preferably, L is aglycerophospholipid selected from the group consisting of:1,2-O-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE) and1,2-O-distearyl-sn-glycero-3-phosphatidylethanolamine (DSPE).

Preferably, the peptide-lipid construct is an exemplifying embodiment ofthe second or third aspect of the invention.

In a second aspect the invention provides a peptide-lipid construct ofthe structure:

L-S—F

where

-   -   F is a peptide;    -   S is a spacer covalently linking F to L via an oligomer of        ethylene glycol; and    -   L is a lipid selected from the group consisting of diacyl- and        dialkyl-glycerolipids, including glycerophospholipids.

Preferably, the structure of the peptide-lipid construct includes thesubstructure:

where M is a monovalent cation (M⁺), n is 6 to 14 and * is other than H.

Optionally, F is a peptide including a proximal terminal sequence (PTS)selected to promote solubility of the peptide.

In a preferment of this option, the PTS of the peptide is selected fromthe group consisting of:

SerLysLysLysLysGly AlaAlaAlaAla GlySerGlySerGly

Preferably, the terminal sequence of the peptide is selected from thegroup consisting of:

GlyLysLysLysLysSerCys       AlaAlaAlaAlaCys    GlySerGlySerGlyCysCysSerLysLysLysLysGly CysAlaAlaAlaAla CysGlySerGlySerGly

Preferably, S is covalently linked to F via a sulphide bond formed withthe Cys residue of the peptide.

More preferably, S is covalently linked to F via a sulphide bond formedwith a Cys residue of the peptide at or proximal to a terminus of thepeptide.

Most preferably, S is linked to F via a sulphide bond formed with a Cysresidue of the peptide at the carboxy-terminus of the peptide.

The spacer (S) is of the structure S₁—S₂—S₃ and selected to provide awater-soluble peptide-lipid construct. S₁ is an oligomer of ethyleneglycol.

Preferably, S₂—S₃ is selected from the group consisting of:

where R₁ is a terminal carbon of S₁, R₂ is the sulphur of the Cysresidue and w is 1 or 2.

Preferably, the structure of the peptide-lipid construct is:

where M is a monovalent cation (M⁺), n is 6 to 14, w is 1 or 2, the sumof x and y is greater than 5, and * is other than H. More preferably, nis 6. Most preferably, y is 0.

Preferably, F is a peptide comprising an epitope of antigens selectedfrom the group consisting of: Glycophorin A, Glycophorin B, or mutationsthereof (including the MNS blood group system).

More preferably, F is a peptide selected from the List of Peptides.

Most preferably, F is a peptide selected from the group consisting of:

GlnThrAsnAspLysHisLysArgAspThrTyrAlaAlaAlaAlaAlaCysGlnThrAsnAspLysHisLysArgAspThrTyrGlySerGlySerGlyCysGlnThrAsnAspMetHisLysArgAspThrTyrGlySerGlySerGlyCys         SerSerGlnThrAsnAspLysHisLysArgAspThrTyrCys                  ThrTyrProAlaHisThrAlaAsnGluValCys                        ProAlaHisThrAlaAsnGluValCys                  SerGlnThrAsnAspLysHisLysArgAspCys

Preferably, L is a glycerophospholipid. More preferably, L is aglycerophospholipid selected from the group consisting of:1,2-O-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE) and1,2-O-distearyl-sn-glycero-3-phosphatidylethanolamine (DSPE).

In an exemplifying first embodiment of the second aspect the inventionprovides a peptide-lipid construct of the structure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-PTS-1MUTK) (M1).

In an exemplifying second embodiment of the second aspect the inventionprovides a peptide-lipid construct of the structure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-PTS-2MUTK) (M2).

In an exemplifying third embodiment of the second aspect the inventionprovides a peptide-lipid construct of the structure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-PTS-3MUTM (M3).

In an exemplifying fourth embodiment of the second aspect the inventionprovides a peptide-lipid construct of the structure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-13MUTK (M13).

In an exemplifying fifth embodiment of the second aspect the inventionprovides a peptide-lipid construct of the structure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-18Mur (M18) (n=6).

In an exemplifying sixth embodiment of the second aspect the inventionprovides a peptide-lipid construct of the structure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-21MUTK (M21) (n=6).

In an exemplifying seventh embodiment of the second aspect the inventionprovides a peptide-lipid construct of the structure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-Hil3 (M23) (n=6).

In an exemplifying eighth embodiment of the second aspect the inventionprovides a peptide-lipid construct of the structure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-PTS-Milt(K,M).

In an exemplifying ninth embodiment of the second aspect the inventionprovides a peptide-lipid construct of the structure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-Milt(K) (M00).

In an exemplifying tenth embodiment of the second aspect the inventionprovides a peptide-lipid construct of the structure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-Milt(M).

In an exemplifying eleventh embodiment of the second aspect theinvention provides a peptide-lipid construct of the structure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-Milt(K,M).

In a third aspect the invention provides a peptide-lipid construct ofthe structure:

L-S—F

where

-   -   F is a peptide;    -   S is a spacer covalently linking F to L via an oligomer of        ethylene glycol; and    -   L is a lipid selected from the group consisting of diacyl- and        dialkyl-glycerolipids, including glycerophospholipids.

Preferably, the structure of the peptide-lipid construct is:

where M is a monovalent cation (M⁺), n is 6 to 14, z is greater than 5,and * is other than H. More preferably, n is 14.

Optionally, F is a peptide including a terminal sequence selected topromote solubility of the peptide.

In a preferment of this option, the terminal sequence of the peptide isselected from the group consisting of:

SerLysLysLysLysGly AlaAlaAlaAla GlySerGlySerGly

Preferably, F is a peptide selected from the group consisting of:

(Xaa)_(z)ValMetTyrAlaSerSerGly;

where z is the integer 4, 5 or 6.

Preferably, F is a peptide selected from the group consisting of:

SerLysLysLysLysGlyValMetTyrAlaSerSerGlyAlaAlaAlaAlaValMetTyrAlaSerSerGly GlySerGlySerGlyValMetTyrAlaSerSerGly

Preferably, L is a glycerophospholipid. More preferably, L is aglycerophospholipid selected from the group consisting of:1,2-O-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE) and1,2-O-distearyl-sn-glycero-3-phosphatidylethanolamine (DSPE).

In an exemplifying first embodiment of the third aspect the inventionprovides a peptide-lipid construct of the structure:

where M is a monovalent cation (M⁺) and designated DOPE-PEG₁₄-Syph.

In a fourth aspect the invention provides a method of preparing apeptide-lipid construct (F—S-L) of the second aspect of the inventionincluding the steps of:

-   -   Preparing a maleimido-derivative of a precursor construct by        reacting a maleimido-donating reagent with a precursor construct        of the structure L-S₁—NH₂; and    -   Reacting the maleimido-derivative of the precursor construct        with a peptide (F) including a Cys residue and solubilised in a        solvent.

where:

-   -   L is a lipid selected from the group consisting of diacyl- and        dialkyl-glycerolipids, including glycerophospholipids; and    -   S₁ is selected from the group consisting of oligomers of        ethylene glycol.

Preferably, the structure of the peptide-lipid construct is:

where n is 6 to 14, w is 1 or 2, the sum of x and y is greater than 5,and * is other than H.

Preferably the maleimido-donating reagent is selected from the groupconsisting of: N-oxysuccinimid ester of maleimidobutyric acid; andN-oxysuccinimid ester of maleimidopropionic acid

Preferably, S₁ is an oligomer of ethylene glycol selected from the groupconsisting of 6 to 14 mer PEG (PEG₆ to PEG₁₄). Most preferably, S₁ isPEG₆.

Preferably, the solvent is selected from the group consisting of:trifluoroethanol; DMSO; or mixtures thereof.

Preferably, the Cys residue is a terminal Cys residue.

Optionally, F is a peptide including a proximal terminal sequence (PTS)selected to promote solubility of the peptide in the reaction solvent.

In a preferment of this option, the PTS of the peptide is selected fromthe group consisting of:

SerLysLysLysLysGly AlaAlaAlaAla GlySerGlySerGly

Preferably, the terminal sequence of the peptide is selected from thegroup consisting of:

GlyLysLysLysLysSerCys       AlaAlaAlaAlaCys    GlySerGlySerGlyCysCysSerLysLysLysLysGly CysAlaAlaAlaAla CysGlySerGlySerGly

Preferably, F is a peptide selected from the List of Peptides.

Preferably, F is a peptide selected from the group consisting of:

GlnThrAsnAspLysHisLysArgAspThrTyrAlaAlaAlaAlaAlaCysGlnThrAsnAspLysHisLysArgAspThrTyrGlySerGlySerGlyCysGlnThrAsnAspMetHisLysArgAspThrTyrGlySerGlySerGlyCys         SerSerGlnThrAsnAspLysHisLysArgAspThrTyrCys                  ThrTyrProAlaHisThrAlaAsnGluValCys                        ProAlaHisThrAlaAsnGluValCys                  SerGlnThrAsnAspLysHisLysArgAspCys

Preferably, L is a glycerophospholipid. More preferably, L is aglycerophospholipid selected from the group consisting of:1,2-O-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE) and1,2-O-distearyl-sn-glycero-3-phosphatidylethanolamine (DSPE).

In a fifth aspect the invention provides a method of effectingqualitative and quantitative changes in the levels of peptide expressedat the surface of cells and multi-cellular structures including the stepof:

-   -   contacting the cells or multi-cellular structures with a        solution of a peptide-lipid construct of the second or third        aspects of the invention at a concentration and for a time and        temperature sufficient to allow the construct to incorporate        into the surface.

Preferably, the peptide-lipid construct is a construct of the secondaspect of the invention.

Preferably the cells or multicellular structures are selected from thegroup consisting of: red blood cells; and embryos. More preferably, thecells or multicellular structures are human cells on multicellularstructures.

Preferably, the time and temperature is no greater than 2 hours at 37°C. or 24 hours at 4° C.

In all aspects of the invention M is typically H, but may be replaced byanother monovalent cation such as Na⁺, K⁺ or NH₄ ⁺.

In the description and claims of the specification the followingacronyms, phrases and terms have the meaning provided:

“Diagnostic marker” means a molecule, the presence of which in a bodyfluid of a subject is diagnostic of a phenotype or pathologicalcondition of the subject.

“MNS blood group system” means blood group antigens or epitopes of thoseantigens and mutations which are present on either glycophorin A,glycophorin B or mutations which result in glycophorin A/B hybrids.

“Proximal terminal sequence” means that portion of the peptide sequenceproximal to the amino- or carboxy-terminus of the peptide (F).

“RBC” means red blood cells.

“Reactive antibody” means an immunoglobulin, the presence of which in abody fluid of a subject is diagnostic of a phenotype or pathologicalcondition of the subject.

“Via an oligomer of ethylene glycol” means a polymer of ethylene glycolconsisting of 2 to 32 mer and specifically excludes via a polymer ofethylene glycol consisting of greater than 32 mer.

“Water soluble” means a stable, single phase system is formed when theconstruct is contacted with water or saline (such as PBS) at aconcentration of at least 100 μg/ml and in the absence of organicsolvents or detergents. The phrase is used synonymously with the term“water dispersible”.

Exemplifying embodiments of the invention are claimed and will now bedescribed in detail with reference to the Figures of the accompanyingdrawings pages.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1. ¹H-NMR spectrum of the peptide-lipid construct designatedDOPE-PEG₆-βAla-Mal-Milt(K) (M13) (5 mg/ml in CD₃OD/CDCl₃/D₂O/0.5MCF₃COOD 60/20/10/1, 600 MHz, 30° C., 6 ppm).

FIG. 2. MALDI TOF mass-spectrum of the peptide-lipid-constructdesignated DOPE-PEG₆-βAla-Mal-Milt(K) (M13) (2856: Peptide-DOPE (M+H);2878: Peptide-DOPE (M+Na); 2894: Peptide-DOPE (M+K); 2900: Peptide-DOPE(M+Na, Na salt); 2916: Peptide-DOPE (M+K, Na salt)).

FIG. 3. ESI mass-spectrum and analytical HPLC of the peptideSerSerGlnThrAshAspLysHisLysArgAspThrTyrGlySerGlySerGlyCys of thepeptide-lipid construct designated DOPE-PEG₆-βAla-Mal-Milt(K) (M13).

FIG. 4. ¹H-NMR spectrum of the peptide SerSerGlnThrAsnAspLysHisLysArgAspThrTyrGlySerGlySerGlyCys of the peptide-lipid construct designatedDOPE-PEG₆-βAla-Mal-Milt(K) (M13) (4.5 mg/ml in D₂O, 600 MHz, 30° C., δppm).

FIG. 5. Photomicrographs of zona free embryos modified to incorporatethe M2 peptide-lipid construct by contacting the embryos with adispersion of the construct at a concentration of 1 mg/mL for 2 hours.The upper photomicrograph is the DIC image. The lower photomicrograph isthe fluorescent image showing 3.0+ fluorescence.

DETAILED DESCRIPTION

In general terms the invention provides peptide-lipid constructs of thestructure (L-S—)_(i)F(—S-L)_(j) where:

-   -   F is a peptide;    -   S is a spacer covalently linking F to L;    -   L is a lipid selected from the group consisting of diacyl- and        dialkyl-glycerolipids, including glycerophospholipids;    -   i and j are independently 0 or 1;

and the use of these peptide-lipid constructs in diagnostic andtherapeutic applications.

Where i is 0 and j is 1 the peptide-lipid constructs are of thestructure:

F—S-L

Where i is 1 and j is 0 the peptide-lipid constructs are of thestructure:

L-S—F

Where S is linked to F via the amino terminus of the peptide theconstruct is represented by the structure or substructure L-S—F.

Where S is linked to F via the carboxyl terminus of the peptide theconstruct is represented by the structure or substructure F—S-L.

Where S is linked to F via a sulphide bond formed via the sulfhydrylgroup of a Cys residue of the peptide the residue is identified with anunderscore (Cys).

Where S is linked to F via a sulphide bond formed with one or more Cysresidues of the peptide, the representation of the peptide-lipidconstruct by the structure L-S—F—S-L, L-S—F or F—S-L is not intended toimply the sulphide bond is formed exclusively with terminal Cysresidues.

The use of the peptide-lipid constructs in diagnostic applications isillustrated with reference to the use of constructs including thesubstructure:

where M is a monovalent cation (M⁺), n is 6 to 14, * is other than H,and the peptide is selected from the group of peptides consisting ofpeptides included in the List of Peptides provided on the followingpages where z is an integer from 0 to 6.

[followed by pages 27 & 28]

List of PeptidesCys(Xaa)_(z)TrpThrProProArgAlaGlnIleThrGlyTyrLeuThrValGlyLeuThrArgArgCys(Xaa)_(z)TrpThrProProArgAlaGlnIleThrGlyTyrArgLeuThrValGlyLeuThrArgArgCys(Xaa)_(z)ValMetTyrAlaSerSerGly                                                         ValMetTyrAlaSerSerGly(Xaa)_(z)Cys                                             AspTyrHisArgValMetTyrAlaSerSerGly(Xaa)_(z)Cys                                          ThrAsnGlyGluThrGlyGlnLeuValHisArgPhe(Xaa)_(z)Cys                                          ThrAsnGlyGluMetGlyGlnLeuValHisArgPhe(Xaa)_(z)Cys                                       AspThrTyrProAlaHisThrAlaAsnGluValSerGlu(Xaa)_(z)Cys                                                ThrTyrProAlaHisThrAlaAsnGluVal(Xaa)_(z)Cys                                                      ProAlaHisThrAlaAsnGluVal(Xaa)_(z)Cys                                                      TyrProAlaHisThrAlaAsnGlu(Xaa)_(z)Cys                                                      ThrTyrProAlaHisThrAlaAsn(Xaa)_(z)Cys                                                   ThrTyrProAlaHisThrAlaAsnGlu(Xaa)_(z)Cys                                                   TyrProAlaHisThrAlaAsnGluVal(Xaa)_(z)Cys                                                   ProAlaHisThrAlaAsnGluValSer(Xaa)_(z)Cys                                                AspThrTyrProAlaHisThrAlaAsnGlu(Xaa)_(z)Cys                                                TyrProAlaHisThrAlaAsnGluValSer(Xaa)_(z)Cys                                                SerGlnThrAsnAspLysHisLysArgAsp(Xaa)_(z)Cys                                             GlnThrAsnAspLysHisLysArgAspThrTyr(Xaa)_(z)Cys      GlnThrAsnAspLysHisLysArgAspThrTyrSerSerGlnThrAsnAspMetHisLysArgAspThrTyr(Xaa)_(z)Cys                                             GlnThrAsnAspMetHisLysArgAspThrTyr(Xaa)_(z)Cys                                                SerSerGlnThrAsnAspLysHisLysArg(Xaa)_(z)Cys                                       SerSerGlnThrAsnAspLysHisLysArgAspThrTyr(Xaa)_(z)Cys                                       SerSerGlnThrAsnAspMetHisLysArgAspThrTyr(Xaa)_(z)CysSerSerGlnThrAsnAspLysHisLysArgAspThrTyrSerSerGlnThrAsnAspMetHisLysArgAspThrTyr(Xaa)_(z)Cys                                                GlnThrAsnAspLysHisLysArgAspThr(Xaa)_(z)Cys                                             SerGlnThrAsnAspLysHisLysArgAspThr(Xaa)_(z)Cys                                             ThrAsnAspLysHisLysArgAspThrTyrPro(Xaa)_(z)Cys                                                GluGluThrGlyGluThrGlyGlnLeuVal(Xaa)_(z)Cys                                                GluGluGluThrGlyGluThrGlyGlnLeu(Xaa)_(z)Cys                                                GluThrGlyGluThrGlyGlnLeuValHis(Xaa)_(z)Cys                                                   SerProProArgArgAlaArgValThr(Xaa)_(z)Cys                              TyrArgTyrArgTyrThrProLysGluLysThrGlyProMetLysGlu(Xaa)_(z)Cys                                                      TrpGlnProProArgAlaArgIle(Xaa)_(z)Cys                                                ThrIleThrGlyLeuGluProGlyThrGlu(Xaa)_(z)Cys

The amino acid residues of peptides are identified according to Table 3of Appendix 2 of Annex C of the Administrative Instructions under thePatent Cooperation Treaty dated 7 Feb. 2007 and in accordance with theconvention:

H₂N-XaaXaaXaa . . . XaaXaaXaa-COOH

There is a need for inexpensive and low level sensitivity test systemsfor a range of diagnostic markers in donated blood, in transfusionrecipients, or in antenatal patients (where the unborn child may be atrisk of haemolytic disease), e.g. syphilis markers and markers of theMNS blood group system. A particular advantage provided by the inventionis the opportunity to employ established blood typing platforms todetect a range of peptide antigen-antibody interactions. The capitalcosts associated with establishing a new diagnostic assay may thereforebe avoided.

Some clinically significant blood group antigens are rare (or rare insome populations). For example mutations of the MNS blood group systemresulting in Miltenberger antigens are rare in Europeans, but common inAsians. Being able to create antibody detection and identificationpanels requires that these antigens be present on the diagnosticscreening cells. Obtaining cells suitable for antibodyscreening/identification having rare antigens is therefore problematic.Being able to add to cells rare antigens prepared exogenously istherefore a major advantage.

According to the method of the invention epitope containing peptidesequences for a range of diagnostic markers, such as specific reactingantibodies, can be localized to the surface of red blood cells (RBCs).These modified RBCs may then be used on existing blood typing platformsto detect blood antobodies or pathologies.

Although the invention is illustrated with reference to the modificationof red blood cells and embryos the outer surface of other cells andmulti-cellular structures is contemplated. However, red blood cells arepreferred for use in diagnostic assays because of the facility withwhich these modified cells could be used in blood typing laboratories.

The level of peptide-lipid construct incorporated into the cell membraneof red blood cells is controlled by the concentration of the constructin the dispersion contacted with the suspension. The presence ofdiagnostic markers may then be assessed by agglutination whether direct(induced by centrifugation of cells) or indirect (induced by adding anantibody directed against the immunoglobulins of the subject). Othermethods of assessment may be employed including, for example, rosetting(Indiveri et al 1979) and enzyme linked immunosorbant assays (ELISA).

In contrast with the preparation of constructs where the function (F) isa carbohydrate, the preparation of constructs where F is a peptidepresents a combination of technical difficulties.

Firstly, it is desirable for the peptide (F) ligated to the L-S or S-Lmoiety to be dispersible in the solvents used for the ligationchemistry. Overcoming this difficulty may require the selection of aproximal terminal sequence (PTS) to promote solubility without modifyingthe desired biological properties of the construct.

Secondly, it is r for the construct (L-S—F—S-L, L-S—F or F—S-L) to bedispersible in water, or at least a biocompatible medium such asbuffered saline, according to the requirements of the proposedapplication (i.e. it is desirable for the construct to be “watersoluble” as defined herein). Overcoming this difficulty requires theselection of a spacer (S) to promote solubility of the construct.

Thirdly, where the proposed application is the modification of cellssuch as red blood cells (RBCs) for use in diagnostic applications,including use as quality controls in blood group typing or detection ofdiagnostic antibodies present in patient serum, it is required for theconstruct to be dispersible without participating in antigen-antibodycross reactivity not specific to the diagnostic marker. Satisfying thisrequirement requires the identification of suitable structural motifsfor the spacer (S) and proximal terminal sequence (PTS) when the latteris present, or the development of sample preparation procedures thatneutralize or at least substantially mitigate the undesired crossreactivity and likelihood of false positives.

It should also be noted that where the application is for use in themodification of the surface of cells or multi-cellular structures (e.g.an embryo) with a view to promoting the association of the modified cellor modified multi-cellular structure with a target surface (e.g. theendometrium) exposing the cell or multi-cellular structure to solventsis incompatible with maintaining the cells or multicellular structuresin a viable state.

The ability to localise peptides to the surface of cells ormulti-cellular structures via a residue proximal to either the N- orC-terminus of the peptide may also allow the naturally occurringconfiguration of the peptide sequence relative to the cell surface to beapproximated. The presentation of the peptide sequence in the tertiary(or quaternary) structure of the parent polypeptide (or protein) maytherefore be mimicked.

Although not demonstrated here it is contemplated that peptides may belocalised to the surface of cells via multiple residues. For example,where both a residue proximal to the amino terminus and a residueproximal to the carboxyl terminus are used to localize the peptide, a“looped” configuration of the peptide may be promoted at the surface.

The use of polyethylene glycol (PEG) as a spacer to promote solubilityis known. However, polymers of PEG may interfere with the expression andfunction of the peptide at the surface. In the peptide-lipid constructsof the invention an oligomer of ethylene glycol (6 to 14 mer) isselected as a component (S₁) of the spacer (S) linking the lipid (L) andpeptide (F).

Oligomers of ethylene glycol impart less solubility to peptide-lipidconstructs of the structure L-S—F than polymers of PEG. The difficultyreferred to above therefore arises when it is desired to obtainpeptide-lipid constructs that are dispersible in biocompatible solventsand can be used in methods of effecting qualitative and quantitativechanges in the levels of peptide expressed at the surface of cells andmulti-cellular structures.

The properties of the peptide-lipid constructs must be such that theycan be readily dispersed in biologically compatible media in the absenceof solvents or detergents, but incorporate into the lipid bilayer of amembrane when a solution of the construct is contacted with a suspensionof cells or multi-cellular structures.

Peptide-lipid constructs with these potentially conflicting propertiesare prepared by adopting the combination of structural motifs describedhere. The preparation of the peptide-lipid constructs where S is linkedto F via a sulphide bond formed with a terminal Cys residue of thepeptide at the carboxy-terminus of the peptide is preferred as thepeptide is less prone to oxidation.

Adopting the combinations of structural motifs in accordance with thedescription provided here a range of peptides may be prepared aspeptide-lipid constructs for use in methods of effecting qualitative andquantitative changes in the levels of peptide expressed at the surfaceof cells and multi-cellular structures.

It will be understood that for a non-specific interaction, such as theinteraction between diacyl- or dialkyl-glycerolipids orglycerophospholipids and a membrane, structural and stereo-isomers ofnaturally occurring lipids can be functionally equivalent. For example,it is contemplated that diacylglycerol 2-phosphate could be substitutedfor phosphatidate (diacylglycerol 3-phosphate). Furthermore it iscontemplated that the absolute configuration of phosphatidate can beeither R or S.

Preparation of DOPE-PEG₆-NH₂ (7)

DOPE-PEG₆-NH₂ (L-S₁—NH₂) (7, 800 mg) was prepared by the method ofSCHEME 1. To a stirred solution of DOPE (5) (36 mg, 0.0484 mmol) in dryCHCl₃ (3 ml) a solution of Fmoc-PEG-NOS (4) (237 mg, 0.0697 mmol(containing about 80% of active N-oxysuccinimide ester)) in dry CHCl₃ (1ml) and Et₃NH (30 ml) was added.

The solution was stirred for 15 h at 20° C., then Et₃NH (3 ml) wasadded, and the mixture was maintained for at 8 h at 20° C. The solutionwas then diluted with toluene (10 ml), evaporated under reduced pressure(10 to 15 torr) and dried under vacuum.

The crude residue was dissolved in H₂O/MeOH/AcOH mixture (10:5:1(v/v/v), 3 ml) and the solution was slowly applied to a reverse phaseC₁₆ column (15 ml, water). Salts, N-hydroxysuccinimide and H₂N-PEG-DOPE(7) were eluted from the column with MeOH/H₂O 1:2 (v/v) (30 ml), 1:1(v/v) (15 ml) and 2:1 (v/v) (15 ml). Target H₂N-PEG-DOPE (7) was elutedfrom the column with MeOH (30 ml) and then with MeOH to MeOH/CHCl₃mixtures (4:1 (v/v), 3:1 (v/v), 2:1 (v/v) and 1:1 (v/v); 30 ml each).Fractions containing H₂N-PEG-DOPE (7) were combined, evaporated underreduced pressure (10 to 15 torr) and dried under vacuum.

The residue obtained as a thin film on the flask walls was extractedtwice with hexane (2×5 ml) and dried under vacuum to yield 143 mg ofH₂N-PEG-DOPE (7) (78% on DOPE) as a white solid. TLC: R_(f)=0.62(ethanol/water/pyridine/AcOH; 3:1:1:1 (v/v/v/v)).

¹H-NMR (500 MHz, CD₃OD, 30° C.): δ=5.541 (m, 4H; 2 —CH═CH—), 5.416 (m,1H; OCH₂CHCH₂O), 4.624 (dd, J=12 Hz, J=3.2 Hz, 1H; CO—OCHCHCH₂), 4.373(dd, J=12 Hz, J=6.6 Hz, 1H; CO—OCHCHCH₂), 4.195 (t, J=5.6 Hz, 2H; POCH₂CH₂N), 4.117 (m, 2H; POCHCHCH₂), 3.968 (m, 4H; OCH ₂CH₂O, OCH ₂CH₂N),3.932 (t, J=6.2 Hz, 2H; OCH ₂CH₂CO), 3.827 (m, 272 H; (—OCH ₂CH₂—)_(n),n=68), 3.683 (m, 2H; OCH ₂OH₂O), 3.622 (t, J=5.6 Hz, 2H; OCH₂CH ₂N),3.397 (t, J=5.0 Hz, 2H; OCH₂CH₂N), 2.678 (t, J=6.2 Hz, 2H; OCH₂CH ₂CO),2.519 (m, 4H; 2 CH₂CO), 2.228 (m, 8H; 2 CH₂CH═CHCH₂), 1.801 (m, 4H; 2CH₂CH₂CO), 1.508 (m, 40H; —CH₂—), 1.096 (˜t, 6H; 2 CH₃) ppm.

Preparation of Peptide-Lipid Constructs

Maleimido-derivatives of DOPE-PEG₆-NH₂ were used for the preparation ofpeptide-lipid constructs (L-S—F) by the method of SCHEME 2 via themaleimide-thiol Michael addition reaction.

Synthesis via the maleimido-derivatives of DOPE-PEG₆-NH₂ has particularadvantages over synthesis via iodoacetate derivatives as difficultiesand low yields as a consequence of oxidation of the sulfhydryl residuesof the peptide and subsequent dimer formation. Reducing agents (e.g.tertiary phosphines) may be used during conjugation.

Maleimido-derivatives were synthesized with 65 to 70% yields startingfrom N-oxysuccinimid esters of maleimidobutyric and maleimidopropionicacids (8a, 8b). An unexpected complication arose due to the presence ofexcess Bu₃P which appeared to be highly reactive towards the maleimidefunction. Phosphine was therefore used only in sub-equivalent amounts(0.1 to 0.2 equivalents).

[followed by page 36]

Trifluoroethanol used as a co-solvent in the preparation of 10bC wherethe peptide was GlnThrAsnAspMetHisLysArgAspThrTyrGlySerGlySerGlyCysappeared to be highly efficient for solubilization of both reactants.However, the solvent also caused unwanted acidification of the reactionmedium which may inhibit the Michael reaction. The isolated yield of10bC in this experiment was ˜25%. Preparation of 10aC where the peptidewas GlnThrAsnAspMetHisLysArgAspThrTyrGlySerGlySerGlyCys(DOPE-PEG₆-βAla-Mal-3MUTM (M3)) carried out using DMSO as co-solvent wasmore successful and provided a 43% yield.

The same solvent strategy in the preparation of 10bC where the peptidewasGlnThrAsnAspLysHisLysArgAspThrTyrSerSerGlnThrAsnAspMetHisLysArgAspThrTyrAlaAlaAlaAlaCys(DOPE-PEG₆-βAla-Mal-PTS-Milt(K,M)) failed because the peptide suppliedappeared to be very acidic and caused solubilization problems. The yieldof 10bC in this experiment was only 23% and about half of the peptidewas recovered.

Molecular weights for the peptide lipid constructs were determined tobe:

DOPE-PEG₆-βAla-Mal-Milt(M)-3029.48 DOPE-PEG₆-βAla-Mal-Milt(K, M)-4591.12

As expected for peptides bearing the glutamine residue at theN-terminus, all preparations contain variable amounts of relatedpyroglytamyl derivatives, M-17 in MS, due to loss of NH₃. The formationof related pyroglytamyl derivatives was mitigated in peptides withN-terminal Ser residues.

The use of the peptide-lipid constructs in methods for effectingqualitative and quantitative changes in the levels of peptide expressedat the surface of cells and multi-cellular structures is illustratedwith reference to the serodiagnosis.

Modification of Red Blood Cells with Peptide-Lipid Constructs (GeneralMethod)

Red blood cells are modified by mixing 1 part by volume of washed packedred blood cells with 1 part by volume of peptide-lipid constructdispersed at a concentration of 10 to 1000 μg/ml in cell media(Celpresol™).

The suspensions are either:

-   -   1. incubated for 2 hours at 37° C. before being washed and        suspended in a cell medium for serological analysis at a        concentration of 0.8 to 3% (Method 1); or    -   2. incubated for 3 to 4 hours at room temperature (circa 25° C.)        followed by 18 hours at 4° C. before being washed and suspended        in a cell medium for serological analysis at a concentration of        0.8 to 3% (Method 2).

Modification of Red Blood Cells with DOPE-PEG₆-βAla-Mal-Milt(K) (M00)

4.7 mg of the lipid-peptide construct DOPE-PEG₆-βAla-Mal-Milt(K) (M00)was reconstituted in 0.47 ml of Celpresol™ by sonicating for 10 min andallowing to stand for 1 hour to provide a clear 10 mg/ml stock solution.

The stock solution was diluted two-fold to provide a solution of 5 mg/mland a dilution series then prepared for the peptide-lipid construct atthe following concentrations:

-   -   1 mg/ml (1:5 dilution in Celpresol™)    -   0.5 mg/ml (1:10 dilution in Celpresol™)    -   0.25 mg/ml (1:20 dilution in Celpresol™)

200 μl of Miltenberger negative red blood cells (Milt⁻ RBCs) were washedtwo times with PBS and one time with Celpresol™. 40 μl of a washedpacked volume of Milt⁻ RBCs were mixed with 40 μl of a dilution of thepeptide-lipid construct and incubated for 2 hours at 37° C.

The modified RBCs were then washed with Celpresol™ and stored inCelpresol™ until used in tube serology testing (3 days and 24 days).

Tube Serology Testing of Modified Red Blood Cells

Serological reactions are graded or scored by either of two establishedsystems (0 or ‘−’=no agglutination, 1+ or 3=very weak agglutination, 2+or 5=weak agglutination, 3+ or 8=moderate strong agglutination, 4+ or10/12=strong agglutination)

Serological platforms used are Tube (addition of reagents and reactantsinto plastic or glass serology tubes and after appropriate incubations,washing and centrifugation observing reactions macroscopically by eyeand a 10× magnification eyepiece and scoring) and BioVue™ (addition ofreactants into cassettes containing beads (including some reactants) andafter appropriate incubations and centrifugation observing the reactionpatterns traped within the Gel matrix). BioVue is the serological columnagglutination platform of Ortho-Clinical Diagnostics.

Serum samples were available from 47 blood donors of negative antibodyscreen status. These samples were designated “negative samples”, but notdetermined not to have anti-Miltenberger antibodies).

Three serum samples known to have Miltenberger related antibodies T217,T6025, T5896. These samples were designated “positive samples”, but notdetermined to have anti-antibodies against the peptide of the peptide ofthe construct designated DOPE-PEG₆-βAla-Mal-Milt(K) (M00).

A suspension of 3% modified RBCs was prepared in PBS and 30 μl of thesuspension mixed with 30 μl serum sample. The mixtures were thenincubated for 45 min at 37° C. Following incubation the RBCs werecentrifuged for 10 s in an Immufuge™ (setting: “high”) and observed foragglutination before being washed 3 times with PBS.

After washing one drop of Epiclone™ anti-human globulin (AHG) was addedand the tubes then centrifuged for 10 s in an Immufuge™ (setting:“high”). Tubes were then read and serology scores recorded.

TABLE 1 Summary of reactivity of samples of serum from 47 blood donorsnot expected to have anti-Miltenberger activity (“negative samples”).Concentration of [followed by DOPE-PEG₆-βAla-Mal-Milt(K)(M00) (mg/ml)page 42] 1.0 0.5 0.25 Age of modified (n = 47) (n = 21) (n = 21) RBCs(days) Serum AHG+ AHG− AHG+ AHG− AHG+ AHG− 3 Negative 1 46 0 21 0 21samples AHG+ means sample reacted by the anti-human globulin test. AHG−means sample is unreactive. RBCs were modified with the peptide-lipidconstruct designated DOPE-PEG₆-βAla-Mal-Milt(K) at the concentrationsindicated. Sera were tested against modified RBCs following 3 daysstorage.

TABLE 2 Results by tube serology of 3 serums known to contain antibodiesagainst antigens of the Miltenberger complex. Age of Concentration ofmodified DOPE-PEG₆-βAla-Mal-Milt RBCs (K) (M00) (mg/ml) (days) Serum 1.00.5 0.25 3 T217 2+ 1+ — 3 T6025 4+ 4+ 4+ 3 T5896 — — — 24 T217 — — n.t.24 T6025 2+ 2+ n.t. 24 T5896 — — n.t. Score results show samplereactivity by the anti-human globulin test, 1+ = weak, 2+ = medium, 3+ =medium/strong, 4+ = strong, — means sample is unreactive. RBCs weremodified with the peptide-lipid construct at the concentrationsindicated. Sera were tested against modified RBCs following 3 days and24 days storage. (n.t.—not tested).

TABLE 3 Results by Diamed column serology of 3 serums known to containantibodies against the Miltenberger complex. Age of Concentration ofmodified DOPE-PEG₆-βAla-Mal-Milt RBCs (K) (M00) (mg/ml) (days) Serum 1.00.5 0.25 3 T217 — — 1+ 3 T6025 1+ 2+ 1+ 3 T5896 — — — 24 T217 — — — 24T6025 2+ 2+ 1+ 24 T5896 — — — Score results show sample reactivity bythe anti-human globulin test, 1+ = weak, 2+ = medium, 3+ =medium/strong, 4+ = strong, — means sample is unreactive. RBCs weremodified with the peptide-lipid construct at the concentrationsindicated. Sera were tested against modified RBCs following 3 days and24 days storage.

Peptide Inhibition

A 5 mg/ml stock solution of the peptideGlnThrAsnAspLysHisLysArgAspThrTyrCys dissolved in Celpresol™ wasprepared. A 4 μl (20 μg peptide) volume of the stock solution was addedto a 30 μl volume of each serum sample (Test). A 4 μl volume ofCelpresol™ was added to 30 μl of each serum sample (Control). Serumsamples (Test and Control) were then incubated at room temperature (RT)for 10 min.

A 30 μl volume of a 5% suspension of the modified RBCs was added to eachsample and incubated at 37° C. for 45 min. The incubated RBCs were thenwashed 3 times with PBS in an Immufuge™. One drop of Epiclone™anti-human globulin (AHG) reagent was then added to each sample and thetubes centrifuged for 10 s in an Immufuge™ (setting: “high”). Tubes wereread and serology scores recorded.

TABLE 4 Results by tube serology of 3 serums known to contain antibodiesagainst the Miltenberger complex and inhibited with peptide.Concentration of DOPE-PEG₆-βAla-Mal-Milt (K) (M00) (mg/ml) Peptide Serum1.0 0.5 CONTROL T217 3+ 2+ T6025 4+ 4+ T5896 — — TEST T217 — — T6025 — —T5896 — — Recorded scores show sample reactivity by the anti-humanglobulin test, 1+ = weak, 2+ = medium, 3+ = medium/strong, 4+ = strong,— means sample is unreactive. RBCs were modified with the peptide-lipidconstruct at the concentrations indicated.

[followed by page 45]

TABLE 5 Identification of polyclonal sera and monoclonal antibodiesemployed as reagents. Re- agent ID Type EIA/Miltenberger Specificity 2T217 Human group AB Reactive with MUT-T peptides serum by EIA 3 T165Human group O serum Reactive with MUR peptides by EIA 4 T7202 Humangroup B serum Reactive with MUT-M peptides by EIA 6 T6025 Human group Aserum Reactive with MUT-T peptides by EIA 7 T8445 Human group O serumUncertain 8 T5896 Human group O serum Uncertain 9 MIII Monoclonalantibody Reactive with Mi III red cells 10 Mia Monoclonal antibodyReactive with Mi III red cells 11 Mur Monoclonal antibody Reactive withMur positive red cells 12 Gam IgG monoclonal Reactive with Mi III redcells antibody 13 BoxH Human serum Uncertain 14 TAP1 Human group O serumPresumed MUT-K specificity 15 TAP2 Human serum Presumed MUR specificity

TABLE 6 Identification of naturally occurring Miltenberger antigenpositive (Milt⁺) human red cells as determined in BioVue AHG cards. Thespecificity of C.BR is uncertain. Polyclonal sera Monoclonal antibodies2 3 4 5 7 8 14 15 9 10 11 12 Cell ID Antigen T217 T165 T7202 T6025 T8445T5896 TAP1 TAP2 MIII Mia Mur Gam 9422184 Vw 8 5 3 0 8 0 5 0 0 10 0 1211297161 MiIII 12 10 12 12 10 10 10 10 10 12 12 4131850 MiIV 12 12 10 010 12 12 1523 MiVI 12 12 8 0 10 12 10 T1569 MiVII 0 0 0 0 10 0 0 0 0 0 0C.BR Mi?X 12 10 12 12 8 12 12 8 0 10 10 10

TABLE 7 Identification of peptide-lipid constructs.  DesignationPeptide sequence M Antigen 1 2 3 4 5 6 7 8 9 10 11 12 13Terminal sequence S₁  1 MUTE Gln Thr Asn Asp Lys His Lys Arg Asp Thr TyrAlaAlaAlaAlaAla* PEG₆  2 MUTK Gln Thr Asn Asp Lys His Lys Arg Asp ThrTyr GlySerGlySerGlyCys PEG₆  3 MUTM Gln Thr Asn Asp Met His Lys Arg AspThr Tyr GlySerGlySerGlyCys PEG₆ 13 MUTE Ser Ser Gln Thr Asn Asp Lys HisLys Arg Asp Thr Tyr Cys PEG₆ 16 Mur Thr Tyr Pro Ala His Thr Ala Asn GluVal Cys PEG 18 Mur Pro Ala His Thr Ala Asn Glu Val Cys PEG 21 MUTK SerGln Thr Asn Asp Lys His Lys Arg Asp Cys  PEG 23 Hil Glu Glu Thr Gly GluThr Gly Gln Leu Val Cys PEG Cys denotes the cysteine residue via thesulfhydryl residue of which the spacer (S) is covalently linked to thepeptide or PTS-peptide (F). *Where Cys is absent the spacer (S) iscovalently linked to the peptide (F) via the terminal amino residue. Allpeptide-lipid constructs (F-S-L or L-S-F) were prepared as the DOPE (L)variant.

TABLE 8 Analysis of sorted data for cells modified to incorporate MUTpeptide constructs and reactivity against the Miltenberger AntibodyPositive Panel. Identity of constructs used in modification of RBCsIdentity of polyclonal sera and monoclonal antibodies (see Table 5) (seeTable 7) 4 8 2 6 3 14 7 9 10 11 12 13 15 M μg/ml T7202 T5896 T217 T6025T165 TAP1 T8445 MIII Mia Mur Gam BoxH TAP2 1 500 5 0 3 8 0 nt 0 0 5 0 8nt nt 2 500 8 8 8 8 5 nt 0 0 5 0 8 nt nt 3 1000 8 10 0 5 nt 0 0 0 0 nt 5nt 13 250 8 3 8 8 0 nt 0 0 0 0 0 8 nt 21 200 0 0 0 8 8 nt 0 0 0 0 3 nt 5‘nt’ denotes not tested.

TABLE 9 Analysis of sorted data for cells modified to incorporate MURpeptide constructs and reactivity against the Miltenberger AntibodyPositive Panel. Identity of constructs used in modification of RBCsIdentity of polyclonal sera and monoclonal antibodies (see Table 5) (seeTable 7) 3 6 7 4 8 2 15 9 10 11 12 13 M ug/ml T165 T6025 T8445 T7202T5896 T217 TAP2 MIII Mia Mur Gam BoxH 16 100 10 5 12 5 0 0 nt 0 0 0 0 018 100 10 10 8 0 0 0 nt 0 0 0 0 nt ‘nt’ denotes not tested.

The majority of polyclonal sera demonstrated cross reactivity with oneor more modified red blood cell populations (Tables 8 and 9).

Where false positives were observed these could be substantiallyeliminated by pre-treatment of the sample of serum with the peptide ofthe peptide-lipid constructs (Table 10 and 11).

TABLE 10 Sera reactive with RBCs modified to incorporate the M1 peptide-lipid construct or M2 peptide-lipid construct constructs by contactingthe cells with a 500 μg/ml dispersion of the construct (Method 1) were“neutralised” with the peptide QTNDKHKRDTY and retested against themodified cells. Sera were neutralized by adding 10 μL of 1 mg/mlsolution of peptide to a 50 μL volume of sera and incubating for 30minutes at 37° C. Testing was performed using BioVue ™ cards. M1modified M2 cells vs cells serum Identity of sera #4 #5 #6 #2 #6 #8Serum alone 5 5 10 8 8 8 Serum + peptide 0 0 0 0 2 0

TABLE 11 Sera reactive with RBCs modified to incorporate the M13peptide- lipid construct by contacting the cells with a 500 μg/mldispersion of the construct (Method 1) were “neutralised” with thepeptide SSQTNDKHKRDTY and retested against the modified cells. M13modified cells Identity of sera #3 #42 #37 #34 Serum alone 8 8 8 8Serum + peptide 0 0 0 0 Sera were neutralized by adding 10 μL of 1 mg/mlsolution of peptide to a 50 μL volume of sera and incubating for 30minutes at 37° C. Testing was performed using BioVue ™ cards.

Modification of Embryos with the Peptide-Lipid Construct DesignatedDOPE-PEG6-βAla-Mal-PTS-Milt(K) (M2)

The zona pellucida of day 3.5 embryos prepared as microdrops wereremoved by incubation in 0.5% pronase solution for circa 5 minutes at37° C. The zona pellucida removed embryos were transferred to microdropscontaining media alone and contacted with a dispersion of thepeptide-lipid construct designated DOPE-PEG6-βAla-Mal-PTS-Milt(K) (M2)at a concentration of 1 mg/ml for 2 hours. The dispersion of thepeptide-lipid construct contained azide as an anti-microbial agent.

The incubated embryos were washed four times in handling media andtransferred to microdrops containing the Gam monoclonal antibody (seeTable 8) and incubated at 37° C. for 40 min. The embryos were thenwashed four times in handling media and transferred to microdropscontaining secondary antibody (FITC anti-mouse) at a 1:50 dilution.

The microdrops were incubated at room temperature in the dark for 30minutes before being washed four times in handling media, placed onmicroscope slides, and overlaid with mineral oil. The embryos werevisualized using an Olympus™ BX51 fluorescent microscope at 200×magnification with WIB filter 550 nm emission wavelength. The scale usedfor grading fluorescence was 0 to 4+, where 0 is no fluorescence and 4+is very bright fluorescence. The mean fluorescence of the modifiedembryos was 2+ versus zero for unmodified embryos. The grading offluorescence is recorded in Table 12.

TABLE 12 Fluorescence of embryos modified by contacting with thepeptide-lipid construct designated DOPE-PEG6-βAla-Mal-PTS-Milt (K) (M2)(10 embryos per group; scale is 0 to 4+). Mean Fluorescence* M2FSL-peptide Media alone 2.0+ 0

A mean fluorescence of 2+ was observed for the zona pellucida removedembryos modified to incorporate the peptide-lipid construct designatedDOPE-PEG6-βAla-Mal-PTS-Milt(K) (M2). No fluorescence was observed forcontrol embryos. The de-compaction of treated embryos was attributed tothe presence of azide in the dispersion of the peptide-lipid construct.

Although the invention has been described by way of exemplifyingembodiments it should be appreciated that variations and modificationsmay be made without departing from the scope of the invention.Furthermore where known equivalents exist to specific features, suchequivalents are incorporated as if specifically referred to in thisspecification.

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1) A method of detecting reactive antibody in the serum of a subjectincluding the steps of: Contacting a sample of the serum with asuspension of cells modified to incorporate a peptide-lipid construct ofthe structure (L-S—)_(i)F(—S-L)_(j) to provide a mixture; Incubating themixture for a time and at a temperature sufficient to allowagglutination; and Determining the degree of agglutination of the cellsin the mixture; where: F is a peptide comprising an epitope for thereactive antibody; S is a spacer covalently linking F to L; and L is alipid selected from the group consisting of diacyl- anddialkyl-glycerolipids, including glycerophospholipids; and i and j areindependently 0 or
 1. 2) The method claim 1 where the method includesthe preliminary step of: Adding an amount of the peptide to the sampleof the serum; where the amount of the peptide is sufficient toneutralize non-specific agglutination or confirm specificity of thereactive antibody. 3) The method claim 1 where includes the intermediatestep of: Adding an anti-subject globulin antibody to the mixture priorto determining the degree of agglutination of the cells of the mixture.4) The method claim 1 where the subject is a human. 5) The method claim1 where the cells are red blood cells. 6) The method claim 1 where theanti-subject globulin antibody is anti-human globulin (AHG) antibody. 7)The method claim 1 where the reactive antibody is reactive to an antigenselected from the group consisting of: Glycophorin A, Glycophorin B, ormutations thereof (including the MNS blood group system). 8) The methodclaim 1 where S is a spacer covalently linking F to L via an oligomer ofethylene glycol. 9) The method claim 1 where the structure of thepeptide-lipid construct includes the substructure:

where M is a monovalent cation (M⁺), n is 6 to 14 and * is other than H.10) The method claim 1 where the structure of the peptide-lipidconstruct is either:

where M is a monovalent cation (M⁺), n is 6 to 14, w is 1 or 2, the sumof x and y is greater than 5, z is greater than 5, and is other than H.11) The method claim 1 where the sum of i and j is
 1. 12) The methodclaim 1 where F is a peptide including a proximal terminal sequence(PTS) selected to promote solubility of the peptide. 13) The methodclaim 12 where the PTS of the peptide is selected from the groupconsisting of: SerLysLysLysLysGly AlaAlaAlaAla GlySerGlySerGly

14) The method claim 1 where F is a peptide comprising an epitope ofantigens selected from the group consisting of: Glycophorin A,Glycophorin B, or mutations thereof (including the MNS blood groupsystem). 15) The method claim 1 where F is a peptide selected from theList of Peptides. 16) The method claim 1 where F is a peptide selectedfrom the group consisting of:GlnThrAsnAspLysHisLysArgAspThrTyrAlaAlaAlaAlaAlaCysGlnThrAsnAspLysHisLysArgAspThrTyrGlySerGlySerGlyCysGlnThrAsnAspMetHisLysArgAspThrTyrGlySerGlySerGlyCys         SerSerGlnThrAsnAspLysHisLysArgAspThrTyrCys                  ThrTyrProAlaHisThrAlaAsnGluValCys                        ProAlaHisThrAlaAsnGluValCys                  SerGlnThrAsnAspLysHisLysArgAspCysAlaAlaAlaAIaValMetTyrAlaSerSerGly GlySerGlySerGlyValMetTyrAlaSerSerGly

17) The method claim 1 where L is a glycerophospholipid. 18) The methodclaim 1 where L is a glycerophospholipid selected from the groupconsisting of: 1,2-O-dioleoyl-sn-glycero-3-phosphatidylethanolamine(DOPE) and 1,2-O-distearyl-sn-glycero-3-phosphatidylethanolamine (DSPE).19) A peptide-lipid construct of the structure:L-S—F where F is a peptide; S is a spacer covalently linking F to L viaan oligomer of ethylene glycol; and L is a lipid selected from the groupconsisting of diacyl- and dialkyl-glycerolipids, includingglycerophospholipids. 20) The peptide-lipid construct of claim 19 wherethe structure of the peptide-lipid construct includes the substructure:

where M is a monovalent cation (M⁺), n is 6 to 14 and * is other than H.21) The peptide-lipid construct of claim 19 where F is a peptideincluding a proximal terminal sequence (PTS) selected to promotesolubility of the peptide. 22) The peptide-lipid construct of claim 21where the PTS of the peptide is selected from the group consisting of:SerLysLysLysLysGly AlaAlaAlaAla GlySerGlySerGly

23) The peptide-lipid construct of claim 19 where the terminal sequenceof the peptide is selected from the group consisting of:GlyLysLysLysLysSerCys AlaAlaAlaAlaCys GlySerGlySerGlyCysCysSerLysLysLysLysGly CysAlaAlaAlaAla CysGlySerGlySerGly

24) The peptide-lipid construct of claim 19 where S is covalently linkedto F via a sulphide bond formed with the Cys residue of the peptide. 25)The peptide-lipid construct of claim 19 where S is covalently linked toF via a sulphide bond formed with a Cys residue of the peptide at orproximal to a terminus of the peptide. 26) The peptide-lipid constructof claim 19 where S is linked to F via a sulphide bond formed with a Cysresidue of the peptide at the carboxy-terminus of the peptide. 27) Thepeptide-lipid construct of claim 19 where S is of the structureS₁—S₂—S₃, S₁ is an oligomer of ethylene glycol and S₂—S₃ is selectedfrom the group consisting of:

where R₁ is a terminal carbon of S₁, R₂ is the sulphur of the Cysresidue and w is 1 or
 2. 28) The peptide-lipid construct of claim 19where the structure of the peptide-lipid construct is:

where M is a monovalent cation (M+), n is 6 to 14, w is 1 or 2, the sumof x and y is greater than 5, and * is other than H. 29) Thepeptide-lipid construct of claim 28 where n is
 6. 30) The peptide-lipidconstruct of claim 28 where y is
 0. 31) The peptide-lipid construct ofclaim 19 where F is a peptide comprising an epitope of antigens selectedfrom the group consisting of: Glycophorin A, Glycophorin B, or mutationsthereof (including the MNS blood group system). 32) The peptide-lipidconstruct of claim 19 where F is a peptide selected from the List ofPeptides. 33) The peptide-lipid construct of claim 19 where F is apeptide selected from the group consisting of:GlnThrAsnAspLysHisLysArgAspThrTyrAlaAlaAlaAlaAlaCysGlnThrAsnAspLysHisLysArgAspThrTyrGlySerGlySerGlyCysGlnThrAsnAspMetHisLysArgAspThrTyrGlySerGlySerGlyCys         SerSerGlnThrAsnAspLysHisLysArgAspThrTyrCys                  ThrTyrProAlaHisThrAlaAsnGluValCys                        ProAlaHisThrAlaAsnGluValCys                  SerGlnThrAsnAspLysHisLysArgAspCys

34) The peptide-lipid construct of claim 19 where L is aglycerophospholipid. 35) The peptide-lipid construct of claim 19 where Lis a glycerophospholipid selected from the group consisting of:1,2-O-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE) and1,2-O-distearyl-sn-glycero-3-phosphatidylethanolamine (DSPE). 36) Apeptide-lipid construct of the structure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-PTS-1MUTK) (M1). 37) A peptide-lipid construct of thestructure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-PTS-2MUTK) (M2). 38) A peptide-lipid construct of thestructure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-PTS-3MUTM (M3). 39) A peptide-lipid construct of thestructure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-13MUTK (M13). 40) A peptide-lipid construct of thestructure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-18Mur (M18) (n=6). 41) A peptide-lipid construct ofthe structure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-21MUTK (M21) (n=6). 42) A peptide-lipid construct ofthe structure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-Hil3 (M23) (n=6). 43) A peptide-lipid construct ofthe structure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-PTS-Milt(K,M). 44) A peptide-lipid construct of thestructure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-Milt(K) (M00). 45) A peptide-lipid construct of thestructure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-Milt(M). 46) A peptide-lipid construct of thestructure:

where M is a monovalent cation (M⁺) and designatedDOPE-PEG₆-βAla-Mal-Milt(K,M). 47) The peptide-lipid construct of claim19 where the structure of the peptide-lipid construct is:

where M is a monovalent cation (M⁺), n is 6 to 14, z is greater than 5,and * is other than H. 48) The peptide-lipid construct of claim 45 wheren is
 14. 49) The peptide-lipid construct of claim 45 where F is apeptide including a terminal sequence selected to promote solubility ofthe peptide. 50) The peptide-lipid construct of claim 47 where theterminal sequence of the peptide is selected from the group consistingof: SerLysLysLysLysGly AlaAlaAlaAla GlySerGlySerGly

51) The peptide-lipid construct of claim 45 where F is a peptideselected from the group consisting of: (Xaa)_(z-7)ValMetTyrAlaSerSerGly;

where z is the integer 4, 5 or
 6. 52) The peptide-lipid construct ofclaim 45 where F is a peptide selected from the group consisting of:SerLysLysLysLysGlyValMetTyrAlaSerSerGlyAlaAlaAlaAlaValMetTyrAlaSerSerGly GlySerGlySerGlyValMetTyrAlaSerSerGly

53) The peptide-lipid construct of claim 45 where L is aglycerophospholipid. 54) The peptide-lipid construct of claim 45 where Lis a glycerophospholipid selected from the group consisting of:1,2-O-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE) and1,2-O-distearyl-sn-glycero-3-phosphatidylethanolamine (DSPE). 55) Apeptide-lipid construct of the structure:

where M is a monovalent cation (M⁺) and designated DOPE-PEG₁₄-Syph. 56)A method of preparing a peptide-lipid construct (F—S-L) of claims 19 to47 including the steps of: Preparing a maleimido-derivative of aprecursor construct by reacting a maleimido-donating reagent with aprecursor construct of the structure L-S₁—NH₂; and Reacting themaleimido-derivative of the precursor construct with a peptide (F)including a Cys residue and solubilised in a solvent. where: L is alipid selected from the group consisting of diacyl- anddialkyl-glycerolipids, including glycerophospholipids; and S₁ isselected from the group consisting of oligomers of ethylene glycol. 57)The method of claim 54 where the structure of the peptide-lipidconstruct is:

where n is 6 to 14, w is 1 or 2, the sum of x and y is greater than 5,and * is other than H. 58) The method of claim 54 where themaleimido-donating reagent is selected from the group consisting of:N-oxysuccinimid ester of maleimidobutyric acid; and N-oxysuccinimidester of maleimidopropionic acid. 59) The method of claim 54 where S₁ isan oligomer of ethylene glycol selected from the group consisting of 6to 14 mer PEG (PEG₆ to PEG₁₄). 60) The method of claim 54 where S₁ isPEG₆. 61) The method of claim 54 where the solvent is selected from thegroup consisting of: trifluoroethanol; DMSO; or mixtures thereof. 62)The method of claim 54 where the Cys residue is a terminal Cys residue.63) The method of claim 54 where F is a peptide including a proximalterminal sequence (PTS) selected to promote solubility of the peptide inthe reaction solvent. 64) The method of claim 61 where the PTS of thepeptide is selected from the group consisting of: SerLysLysLysLysGlyAlaAlaAlaAla GlySerGlySerGly

65) The method of claim 54 where the terminal sequence of the peptide isselected from the group consisting of: GlyLysLysLysLysSerCys      AlaAlaAlaAlaCys    GlySerGlySerGlyCys CysSerLysLysLysLysGlyCysAlaAlaAlaAla CysGlySerGlySerGly

66) The method of claim 54 where F is a peptide selected from the Listof Peptides. 67) The method of claim 54 where F is a peptide selectedfrom the group consisting of:GlnThrAsnAspLysHisLysArgAspThrTyrAlaAlaAlaAlaAlaCysGlnThrAsnAspLysHisLysArgAspThrTyrGlySerGlySerGlyCysGlnThrAsnAspMetHisLysArgAspThrTyrGlySerGlySerGlyCys         SerSerGlnThrAsnAspLysHisLysArgAspThrTyrCys                  ThrTyrProAlaHisThrAlaAsnGluValCys                        ProAlaHisThrAlaAsnGluValCys                  SerGlnThrAsnAspLysHisLysArgAspCys

68) The method of claim 54 where L is a glycerophospholipid. 69) Themethod of claim 54 where L is a glycerophospholipid selected from thegroup consisting of:1,2-O-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE) and1,2-O-distearyl-sn-glycero-3-phosphatidylethanolamine (DSPE). 70) Amethod of effecting qualitative and quantitative changes in the levelsof peptide expressed at the surface of cells and multi-cellularstructures including the step of: contacting the cells or multi-cellularstructures with a solution of a peptide-lipid construct of any one ofclaims 19 to 55 at a concentration and for a time and temperaturesufficient to allow the construct to incorporate into the surface. 71)The method of claim 54 where the peptide-lipid construct is a constructof any one of claims 19 to
 47. 72) The method of claim 54 where thecells or multicellular structures are selected from the group consistingof: red blood cells; and embryos. 73) The method of claim 54 where thecells or multicellular structures are human cells or multicellularstructures. 74) The method of claim 54 where the time and temperature isno greater than 2 hours at 37° C. or 24 hours at 4° C.